1. Field of the Invention
The present invention relates to an endoscope insertion support system and an endoscope insertion support method for supporting the insertion of an endoscope into the tubular path of a tubular organ.
2. Description of the Related Art
In recent years, diagnosing by photographic images has come into extensive practice; for instance, three-dimensional image data within a subject are obtained by picking up tomograms of the subject with an X-ray CT (computed tomography) apparatus or the like, and the intended diagnosis is performed by using the three-dimensional image data.
With a CT apparatus, by consecutively shifting the subject in the direction of its bodily axis while consecutively turning X-ray irradiation and detection, a spiral continuous scan (helical scan) is performed on a three-dimensional area of the subject, and a three-dimensional image is produced from consecutively sliced tomograms of the three-dimensional area.
One of such three-dimensional images is a three-dimensional image of the bronchus of a lung. A three-dimensional image of a bronchus is used for three-dimensionally identifying the position of a disordered part suspected of presence of lung cancer or the like. Then, in order to check the disordered part by biopsy, a bronchoscope is inserted and a sample of the tissue is picked up by extruding from its distal end portion a bioptic needle, bioptic forceps or the like.
In a tubular path such as a bronchus having multi-step branches in the body, when the location of the disordered part is near the periphery of a branch, it is difficult to enable the distal end portion of the endoscope to reach the target region in a short period of time.
For this reason, for instance Japanese Patent Application Laid-Open No. 2000-135215 as Document 1 proposes an apparatus by which (1) a three-dimensional image of a tubular path in a subject is produced on the basis of image data of a three-dimensional area in the subject, (2) the route to the target point is figured out along the tubular path on the three-dimensional image, (3) a virtual endoscopic image of the tubular path along the route is produced on the basis of the image data, and (4) a bronchoscope is navigated to the target region by displaying the virtual endoscopic image.
Also, in order to produce a three-dimensional image of a tubular path in a subject on the basis of image data of a three-dimensional area in the subject, it is necessary to extract area information of the targeted organ, for instance the bronchus (information of how the bronchial branches and connected to constitute the whole bronchus), from the image data of the three-dimensional area.
Then, in “T. Kitasaka, K. Mori, J. Hasegawa and J. Toriwaki; A Method for Extraction of Bronchus Regions from 3D Chest X-ray CT Image by Analyzing Structural Features of the Bronchus”, Form a 17, pp. 321-338 (2002) as Document 2 for instance and elsewhere, there is proposed a method, so-called segmentation processing, whereby a VOI (Volume of Interest) of a prescribed size comprising prescribed voxels is set on a three-dimensional area in a subject and area information on a target organ, for instance the bronchus is extracted from image data of the three-dimensional area in the subject within the VOI while installing the VOI in the running direction of the tubular organ.